Atomic Structure Matter is anything that occupies space

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Atomic Structure

Atomic Structure

Matter is anything that occupies space

Matter is anything that occupies space

Composition of Matter is composed of particles, which may be atoms, molecules or ions

Composition of Matter is composed of particles, which may be atoms, molecules or ions

Law of Conservation of Mass The law of conservation of mass states that matter

Law of Conservation of Mass The law of conservation of mass states that matter is neither created nor destroyed in the course of a chemical reaction.

Scientists that led to the modern view of the atom? • Dalton • Crooke

Scientists that led to the modern view of the atom? • Dalton • Crooke • Stoney • Thomson • Millikan • Rutherford • Bohr • Chadwick

Dalton’s Atomic Theory The law of conservation of mass states that matter is neither

Dalton’s Atomic Theory The law of conservation of mass states that matter is neither created nor destroyed in the course of a chemical reaction. Dalton proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass. Dalton stated that all compounds were composed of combinations of these atoms in defined ratios. Dalton also postulated that chemical reactions resulted in the rearrangement of the reacting atoms.

William Crooke discovered cathode rays and found evidence that these cathode rays were actually

William Crooke discovered cathode rays and found evidence that these cathode rays were actually particles

J J Thomson discovered that electrons had negative charge. He calculated the e/m for

J J Thomson discovered that electrons had negative charge. He calculated the e/m for electrons.

J J Thomson proposed that atoms consist of small negative electrons embedded in a

J J Thomson proposed that atoms consist of small negative electrons embedded in a massive positive sphere

George Stoney proposed the name of ‘electron’ for the negatively charged particles

George Stoney proposed the name of ‘electron’ for the negatively charged particles

Cathode Rays Streams of negatively charged particles (electrons) that travel from the cathode to

Cathode Rays Streams of negatively charged particles (electrons) that travel from the cathode to the anode a vacuum tube.

Robert Millikan Determined the size of the charge on the electron using the oil

Robert Millikan Determined the size of the charge on the electron using the oil drop experiment.

Ernest Rutherford discovered the nucleus of the atom by bombarding gold foil with alpha

Ernest Rutherford discovered the nucleus of the atom by bombarding gold foil with alpha particles and the scattering indicated a hard-dense core in the centre of the atom. Rutherford bombarded different elements and found that they all gave out the same positively charged particle which was identical to the nucleus of the hydrogen atom. He called this particle the proton

Niels Bohr proposed that the electrons in atoms were arranged in a series of

Niels Bohr proposed that the electrons in atoms were arranged in a series of concentric circular orbits at an increasing distance from the nucleus

James Chadwick brought about the release of neutral particles with the same mass as

James Chadwick brought about the release of neutral particles with the same mass as the proton by bombarding sample of beryllium with alpha particles. He named them neutrons.

Atom Smallest particle of matter that can take part in a chemical reaction

Atom Smallest particle of matter that can take part in a chemical reaction

Properties of Sub atomic Particles Particle Relative Charge Relative Mass Location Neutron 0 1

Properties of Sub atomic Particles Particle Relative Charge Relative Mass Location Neutron 0 1 Nucleus Proton +1 1 Nucleus Electron -1 1/1838 Shells

Atomic Number of Protons in Atom

Atomic Number of Protons in Atom

Mass Number of protons and neutrons in an atom

Mass Number of protons and neutrons in an atom

Isotopes Atoms with the same atomic number but different mass number due to the

Isotopes Atoms with the same atomic number but different mass number due to the different number of neutrons in the nucleus

Isotopes of Hydrogen

Isotopes of Hydrogen

Isotopes of Carbon

Isotopes of Carbon

Relative Atomic Mass Is the average mass of the isotopes of an element as

Relative Atomic Mass Is the average mass of the isotopes of an element as they occur in nature taken abundances into account when compared to one twelfth of the mass of the 12 C atom

Mass Spectrometer Principle Positively charged ions are separated on the basis of their relative

Mass Spectrometer Principle Positively charged ions are separated on the basis of their relative masses as they move in a magnetic field

Processes in Mass Spectrometer Processes 1. Vaporisation 2. Ionisation 3. Acceleration 4. Separation 5.

Processes in Mass Spectrometer Processes 1. Vaporisation 2. Ionisation 3. Acceleration 4. Separation 5. Detection

Uses of Mass Spectrometer Uses Identify compounds e. g. 1. in analysis of gases

Uses of Mass Spectrometer Uses Identify compounds e. g. 1. in analysis of gases from waste dumps 2. in trace organic pollutants in water 3. in drug testing Measure relative atomic mass Measure relative abundance of isotopes